1. Technical Field
The present invention relates to a printing apparatus.
2. Related Art
Ink jet printing apparatuses are employed to print images or the like on a medium by ejecting a liquid such as ink from ejection heads that are provided with nozzles, toward the surface of a medium such as paper or fabric. Such printing apparatuses include maintenance sections that perform maintenance on the ejection heads to forestall ejection defects of the ink from the nozzles, or when ejection defects have arisen. Printing operation is stopped while performing maintenance operations on the ejection heads. In large scale printing apparatuses provided with plural ejection heads, maintenance can take a long time, and so proposals have been put forward for reducing printing operation downtime. For example, JP-A-2006-341543 describes an ink jet printing apparatus including two sets (two systems) of head units. During a maintenance operation on one of the head units, the other head unit performs a printing operation.
However, although the printing apparatus described in JP-A-2006-341543 is capable of reducing the maintenance time when a maintenance operation is performed partway through a printing operation, issues remain in that a long maintenance time is still required for maintenance operations prior to commencing printing, resulting in a drop in operation efficiency of the printing apparatus. Moreover, providing two head unit systems incurs an increase in the cost of the printing apparatus.